Annexin V (human, recombinant)

Annexin V is a soluble membrane-binding protein encoded by the ANXA5 gene in humans that binds to negatively charged phospholipids, such as phosphatidylserine (PS), in a calcium-dependent manner.^1,2,3 It is expressed in a wide variety of tissues but is detected primarily in placenta and vascular endothelium.⁴ Annexin V is comprised of a variable N-terminal domain and four highly conserved annexin repeats that form the membrane-binding core.^1,5 Upon membrane binding, annexin V forms a two-dimensional lattice that is stabilized by protein-protein interactions.^2,5 In activated platelets and apoptotic cells, plasma membrane asymmetry, but not integrity, is disrupted and PS becomes exposed at the cell surface, following which annexin V binds to the surface-exposed PS and inhibits its procoagulant and pro-inflammatory activities.^2,4,6,7 Because of its affinity for PS in apoptotic cell membranes, fluorescent and affinity-labeled versions of annexin V have been used in affinity assays for the detection and quantification of apoptotic cells.⁷ Annexin V levels are elevated in tumor tissue from patients with a variety of cancers, including follicular thyroid adenoma, papillary thyroid carcinoma, cervical squamous cell carcinoma, and colorectal cancer.⁵ Cayman's Annexin V (human, recombinant) protein can be used for Western blot, ELISA, and cell-based assays.

WARNING This product is not for human or veterinary use.

1. Bouter, A., Carmeille, R., Gounou, C., et al. Review: Annexin-A₅ and cell membrane repair. Placenta 36(Suppl. 1), S43-S49 (2015).

2. Reutelingsperger, C.P., and van Heerde, W.L. Annexin V, the regulator of phosphatidylserine-catalyzed inflammation and coagulation during apoptosis. Cell. Mol. Life Sci. 53(6), 527-532 (1997).

3. Bodganova, N., Horst, J., Chlystun, M., et al. A common haplotype of the annexin A₅ (ANXA5) gene promoter is associated with recurrent pregnancy loss. Hum. Mol. Genet. 16(5), 573-578 (2007).

4. Esposito, G., Tamby, M.C., Chanseaud, Y., et al. Anti-annexin V antibodies: Are they prothrombotic? Autoimmun. Rev. 4(1), 55-60 (2005).

5. Peng, B., Guo, C., Guan, H., et al. Annexin A₅ as a potential marker in tumors. Clin. Chim. Acta 427, 42-48 (2014).

6. Andree, H.A., Stuart, M.C., Hermens, W.T., et al. Clustering of lipid-bound annexin V may explain its anticoagulant effect. The Journal of Biological Chemisty 267(25), 17907-17912 (1992).

7. van Engeland, M., Nieland, L.J.W., Ramaekers, F.C.S., et al. Annexin V-affinity assay: A review on an apoptosis detection system based on phosphatidylserine exposure. Cytometry 31(1), 1-9 (1998).